There is known a control apparatus for a vehicular drive system provided with a transmission mechanism constituting a part of a power transmitting path between an engine and drive wheels, and an electric motor operable to change an operating speed of the engine in the process of shifting of the transmission mechanism. Patent Document 1 discloses an example of such a control apparatus in the form of a drive control apparatus for a hybrid vehicle. The above-indicated transmission mechanism provided in the vehicular drive system disclosed in this Patent Document 1 is an automatic step-variable transmission which includes a plurality of planetary gear sets and a plurality of frictional coupling elements and which performs shifting actions by engaging and releasing actions of the frictional coupling elements. The above-indicated drive control apparatus disclosed in the Patent Document 1 is configured to operate the above-indicated electric motor so as to raise operating speed of the engine during a manual shift-down action of the automatic transmission performed in response to a manual operation of an operator of the vehicle, so that the shift-down action of the automatic transmission can be expedited.